A large number of medicament delivery devices for self-medication have been developed during the years, where many have a high degree of automatic functions and features in order to facilitate the use of the medicament delivery device, especially for unexperienced users.
One device that has gained a lot of attention on the market for its functionality is disclosed in the document WO 2011/005177 A1. The device disclosed therein has a number of automatic features like auto-penetration, auto-injection and automatic covering of the injection needle after removal of the medicament delivery device from the dose delivery site.
Even though working very well, the medicament delivery device according to WO 2011/005177 A1 comprises quite a lot of components that on the one hand provides an increased complexity regarding interaction between the components as well as increased assembly complexity and on the other hand increased manufacturing costs due to the number of components.
Further, there is an increased demand for medicament delivery devices that can handle medicament containers of different sizes, i.e. containing different volumes of medicament. One problem in that respect is that the length of the medicament container differs in that the position of a plunger rod when contacting a stopper that is movable inside a medicament container is different depending on the size of volume of the medicament to be delivered. Usually many parts of a medicament delivery device need to be redesigned in order to handle different medicament containers, including plunger rods, activation buttons and the like. It would be an advantage if the number of components could be kept as low as possible at the same time as the flexibility of the medicament delivery devices regarding handling of medicament container of different sizes could be improved.